10 A Novel High-Efficiency Keyhole Tungsten Inert Gas …
353
10.4.3 Misorientation Angle Distribution of Grain Boundary
(MADGB)
A large number of studies has shown that the MADGB has a significant effect on the
mechanical properties of polycrystalline materials. Base on the orientation angles
(θ ), Grain Boundaries (GB) are generally divided into two types. One is a low-angle
grain boundary (LAGB, 2° ≤ θ ≤ 5°), and the other is a high-angle grain boundary
(HAGB, θ ≥ 15°) [40]. When the θ is 60°, it is called 3 coincidence site lattice
(CSL) boundary. It has lower GB energy and less impurity segregation. The 3 CSL
boundary can hinder the migration of HAGB, and HAGB can obstruct the expansion
of brittle cracks [41].
MADGB maps of the ferrite and austenite in S32101 duplex stainless steel K-TIG
welded joint were shown in Figs. 10.37 and 10.38. The MADGB of ferrite in the BM
is relatively uniform and the MADGB of ferrite in the HAZ, the number of HAGB
decreased slightly. In the WM, the MADGB is mainly in LAGB. In Fig. 10.38a,
the MADGB of austenite in the BM is mainly in LAGB, and the frequency of 3
Fig. 10.37 MADGB of the ferrite in S32101 duplex stainless steel K-TIG welded joint. a BM,
b HAZ, c WM
353
10.4.3 Misorientation Angle Distribution of Grain Boundary
(MADGB)
A large number of studies has shown that the MADGB has a significant effect on the
mechanical properties of polycrystalline materials. Base on the orientation angles
(θ ), Grain Boundaries (GB) are generally divided into two types. One is a low-angle
grain boundary (LAGB, 2° ≤ θ ≤ 5°), and the other is a high-angle grain boundary
(HAGB, θ ≥ 15°) [40]. When the θ is 60°, it is called 3 coincidence site lattice
(CSL) boundary. It has lower GB energy and less impurity segregation. The 3 CSL
boundary can hinder the migration of HAGB, and HAGB can obstruct the expansion
of brittle cracks [41].
MADGB maps of the ferrite and austenite in S32101 duplex stainless steel K-TIG
welded joint were shown in Figs. 10.37 and 10.38. The MADGB of ferrite in the BM
is relatively uniform and the MADGB of ferrite in the HAZ, the number of HAGB
decreased slightly. In the WM, the MADGB is mainly in LAGB. In Fig. 10.38a,
the MADGB of austenite in the BM is mainly in LAGB, and the frequency of 3
Fig. 10.37 MADGB of the ferrite in S32101 duplex stainless steel K-TIG welded joint. a BM,
b HAZ, c WM